Dark Red Line (Bangkok)

SRT Dark Red Line
SRT Dark Red Line train at the Rangsit railway station
Overview
Other nameThani Ratthaya Line
Native nameสายธานีรัถยา
StatusOperational (Phase 1)
OwnerState Railway of Thailand
LocaleBangkok Metropolitan Region
Termini
Stations10
Service
TypeCommuter rail
SystemSRT Red Lines
Operator(s)SRTET - SRT Electrified Train Company Limited
Depot(s)Chatuchak, Bangkok
Rolling stockHitachi AT100
History
Opened2 August 2021 (2021-08-02) (free trial service)
29 November 2021 (2021-11-29) (commercial service)
Technical
Line length26 km (16 mi)
Number of tracks2
CharacterElevated
Track gauge1,000 mm (3 ft 3+38 in) metre gauge
Electrification25 kV 50 Hz AC overhead catenary
Operating speed160 km/h (99 mph)
SignallingThales AlTrac for ERTMS (ETCS Level 1)
Route map

km
future North extension
32.6
Thammasat University
29.9
Chiang Rak
Bangkok University
26.2
Khlong Nueng
22.6
Rangsit
19.9
Lak Hok (Rangsit University)
13.8
Don Mueang
11.8
Kan Kheha
9.9
Lak Si
 MRT 
7.1
Thung Song Hong
5.6
Bang Khen
4.1
Wat Samian Nari
2.6
Chatuchak
Bang Sue Junction
0.0
Krung Thep Aphiwat
Central Terminal
 SRT   MRT 
Pradiphat
2.7
Sam Sen
3.7
Ratchawithi
Ramathibodi Hospital Halt
Yommarat Halt
SRT Eastern Line
5.4
Yommarat
Urupong Halt
6.5
Yotse
7.5
Hua Lamphong
 MRT 
future South extension
Khlong San
 BTS 
Wongwian Yai
 BTS   MRT 
Wongwian Yai
SRT Maeklong Railway
Talat Phlu
Wutthakat
 BTS 
Taksin
Khlong Ton Sai
Chom Thong
Wat Sai
Wat Singh
Bang Bon
Khan Keha
Rang Sakae
Rang Pho
Sam Yaek
Phrom Daen
Thung Si Thong
Bang Nam Chuet
Khok Khwai
Ban Khom
Khlong Chak
Maha Chai

The SRT Dark Red Line (also referred to as Thani Ratthaya Line (Thai: รถไฟชานเมือง สายธานีรัถยา)) is part of the SRT Red Line suburban railway system to serve the greater Bangkok Metropolitan Region running for 26 km (16 mi) between Krung Thep Aphiwat Central Terminal and Rangsit.

Phase I of the line opened for trial operations on 2 August 2021, with full commercial services beginning on 29 November 2021.

Tenders for the much delayed 8.84 km (5.49 mi) Phase II extension of the line from Rangsit to Thammasat University were opened in December 2025. Submissions to the SRT were due by 29 December 2025, with bid winners announced in January 2026 and a notice to proceed expected to be issued in March 2026 once contracts are signed. Construction is expected to take 36 months with a target to start operation by March 2029.